The most important things to know about any speech are:
Let's look at each of those elements.
Time limits restrict how much information can be shared without boring or overwhelming listeners.
Knowing the audience helps you understand what they know, what they will need to know, and how best to communicate with them. An audience of middle managers is going to want the same topic covered in a very different way from high-school students.
The objective is often supplied by others. If you are briefing senior management on the three projects you manage, they will need to know the status relative to the schedule, upcoming milestones, and the risks going forward.
The standard structure for a speech looks something like the old advice "Tell them what you are going to tell them, tell them, then tell them what you just told them." In other words, give a preview of the information you will share, cover each item in more depth, then review the main points. That's all.
Knowing that basic format will make it easier to start outlining your speech.
And, if you want another guide to giving a great speech there is a Forbes article that can help. Consider making and printing your own version of that checklist.